The invention relates to metal containers that can be used in both microwave and conventional ovens.
It has been generally promulgated that metal containers cannot, or should not, be used in microwave ovens for reasons of arcing and unsatisfactory cooking results. Various patents have disclosed means to effect exceptions to this general rule. These patents dictate significant constraints on the design of the metal pans and/or their manner of use.
U.S. Pat. Nos. 3,857,023 and 3,985,991 show the use of a shallow aluminum foil pan inside of a microwave permeable box. The box provides the environment for a vapor cycle heat exchange process that cooks the portion of the food shielded from the microwave energy by the foil pan.
U.S. Pat. Nos. 4,558,198 and 4,560,850 show the use of a shallow metal pan having an electrically-insulating and microwave-diffusing inner and outer continuous plastic coating. The pan is used in conjunction with a plastic lid that retains steam to help heat the food, and in the case of the latter patent, to force steam to flow under the pan from a hole in the center of the pan. The lid covering the edges of the pan also serves to space the pan from the oven's walls. The walls of the pan are specified to be curved and all junctions between surfaces are specified to be of substantial radius in order for the pan to function without arcing in a microwave oven.
All of the prior art devices require substantial divergence from the pans and techniques of conventional baking in order to produce satisfactory results. This additional complexity, whether perceived or actual, discourages many users from making full use of the time and energy saving capabilities of microwave baking.